- Date
- November 9, 1993, 09:00 local (17:00 UTC)
- Place
- Toledo, WA
- Injuries
- 1 uninjured
- Damage
- Substantial damage
- Phase of flight
- Maneuvering
- Aircraft
- N8169JBell 47G3B2
- Weather
- Visual (VMC) · Day
- Status
- Completed · report December 2, 1994
- Report
- Approved by Office Director
- FAA report
- 19931109042759A
- Case key
- 41852
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
Transmission shear bolts failed causing a loss of power to the rotor system, and the pilot encountered unsuitable terrain during his autorotation attempt.
Sequence of events
NTSB’s coding before 2008: each occurrence and phase of flight, and the causes and factors under it. The codes are defined in NTSB’s coding manual.
Analysis
While lifting christmas trees under external load conditions the pilot heard a clunk and experienced a loss of power. He attempted an autorotation from 40 to 50 feet into the christmas tree farm, striking and bending the tail boom when it impacted a tree. Investigation revealed that the transmission shear bolts, pn 47-620-485-9, had sheared. The pilot attributed the failure of the shear bolts to power impulses from repeated compressor stalls.
Factual narrative
On November 9, 1993, at 0930, a Bell B-47G3B2, N8169J, operated by Farm & Forest Helicopter Service, impacted terrain at Toledo, Washington, during an emergency forced landing. There was no flight plan filed for the local external load flight, conducted under 14 CFR 133, that was on takeoff from a field site when the accident occurred. The commercial certificated pilot was not injured in the accident. The aircraft was substantially damaged. There was no fire.
The pilot reported he was on takeoff with an external load of Christmas trees when he heard a grinding sound and the main rotor RPM began to decrease. He initiated an autorotation from about 40 to 50 feet into the christmas trees. On landing, the tair boot hit a tree and bent. An examination of the wreckage revealed fractured main transmission shear bolts.
The pilot attributed the failure to power impulses after repeated compressor stalls or partial flame-outs of the turbine engine.
Aircraft
- Registration
- N8169J
- Reported as
- Bell 47G3B2
- Category
- Helicopter
- Serial number
- 6775
- Airframe hours
- 3,013
- Engine
- Allison 250-C20B, 420 horsepower, turbo shaft
- Damage
- Substantial damage
- Flight
- Other work use · Part 133
- Operator
- Farm & Forest Helicopter Svc
- Registered owner
- Farm & Forest Helicopter Svc
- Airworthiness certificate
- Standard, Normal
- Last inspection
- 100 hour · November 1, 1993 · 27 hours before
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 43
- Certificates
- Private, Commercial
- Airplane ratings
- Single-engine land
- Medical
- Class 2, Valid Medical--no waivers/lim.
- Seat
- Left
- Flight hours
- 7,821 total · 952 in this make and model · 7,696 as pilot in command · 123 in the last 90 days · 36 in the last 30 days · 4 in the last 24 hours
Weather
- Conditions
- Visual (VMC) · Day
- Wind
- 225° at 2 knots, gusting 5
- Visibility
- 10 statute miles
- Lowest ceiling
- 600 ft overcast
- Temperature
- 39 °F
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N8169J · 2
Matched to the same aircraft by N-number and date.